Description is provided hereinafter of a conventional angular velocity sensor.
The conventional angular velocity sensor detects an angular velocity by vibrating a sensing element of such a shape as a tuning fork, a letter H and a letter T, for example, and electrically detecting a distortion of the sensing element caused by a Coriolis force.
When a vehicle is disposed on an X-Y plane between X axis and Y axis within a space of the mutually orthogonal axes of X, Y and Z, for instance, the angular velocity sensor for navigation device is required to detect angular velocities around the X axis and the Z axis of the vehicle.
For detecting angular velocities of a plurality of axes (e.g., X axis, Y axis and Z axis) it has been the general practice in the past to use a plurality of angular velocity sensors, each corresponding to the respective axis of detection. In addition, a sensing element has been positioned vertically on the X-Y plane when detecting an angular rate around the Z axis.
Patent reference 1, for instance, is one of the prior art documents known to be related to the invention of the present application.
In the case of the above structure, however, it is necessary to provide a mounting area sufficient for installing a plurality of sensing elements or a plurality of angular velocity sensors on a mount board when detecting angular velocities of a plurality of axes, so that it is difficult to make downsizing of the variety of electronic devices.
Patent Reference 1: Unexamined Japanese Patent Publication, No. 2001-208546